Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Sun, 12 May 2002 18:27:23 -0400
Message-ID: <redirect-1235766@logan.com>
From: "Larry Henney" <LHenney@dellepro.com>
Subject: RE: [LML] LNC2 Hydraulics
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Ian writes

>As I understand it from other members who have had hydraulic problems 
>it is usually the double >acting cylinders that allow pressure to flow 
>from the HP side to the LP side.  That is unless >you have an obvious 
>external leak.

I went through this process to find an internal leak and found all 6
cylinders to be fine.  The double acting cylinders may well be the
biggest failure component if you have the new free fall valve.  My free
fall valve was the culprit and was underrated at 600 PSI.  Lancair now
sells a higher rated valve as a replacement.  I got mine locally from WW
Granger.

The inline test valve discussion sounds really scary to me.  Adding all
that maintenance trouble shooting capability sounds heavy and adds
connectors increasing risk of failure.  I suggest buying 20 caps from
ACS and laying painters plastic under the plane.  By depressurizing the
system (dump valve) before disconnecting each cylinder the leakage will
be nil.  And no I didn't believe it either until I did it.

I really can't convince myself of good reasons to have hyd. pressure
gauges in the airplane. What added information do they tell us?  When I
tweaked my system set points using a gauge I found that the Hi/Lo set
switches had a very tight pressure band.  The gauge held no relevance to
that maintenance function.  Further, in flight the pump cycling is my
trigger that something needs tending to (perhaps a leak). 

My repetitive theme here is don't add stuff that's not really useful for
flight.  It just cuts down your speed and loading capability.  On the
other hand, go ahead.  

Looking forward to the Airventure Cup.

Larry Henney
N360LH